Saving costs without compromising safety

By Modern Metals' staff

ArcelorMittal unveils new ultra-lightweight car door solutions

August 2013 – Automakers are putting their future car designs on a strict diet. They’ll need to reduce vehicle weight in order to meet regulations that will come into effect in 2015 for European cars and 2021 for U.S. cars, with even-tougher standards on tap for 2025.

Using steels and technologies currently available, ArcelorMittal’s global research and development automotive team has demonstrated that a 27 percent weight and cost savings can be achieved without compromising safety and structural requirements.

“As the leading supplier of steels to the global automotive industry, we have worked with all carmakers for many years to help them reduce the weight of their vehicles,” said Brian Aranha, vice president automotive worldwide, in a press release. “ArcelorMittal’s S-in motion study, launched in November 2010, has already identified a whole range of innovative steel solutions that are significantly reducing the weight of the body-in-white of current and future production vehicles, including hang-on parts such as doors. This is the next step for us in continuing to offer weight-saving solutions and subsequently cost savings to our customers. Automotive is one of our franchise businesses, and we are discussing with all the major OEMs to work with them to integrate these new solutions into the design of future cars.”

Steel stands strong

The research team at ArcelorMittal demonstrated that more than 30 percent cost savings compared to an aluminum car door can be achieved—without compromising safety and structural requirements. The company’s short-term solution uses ultra-high-strength steel grades, including MS 1500 and Usibor, for structural parts and dual-phase steels for the outer panel. This solution also includes a new thin-gauge laser-welded-blank inner panel.

In addition to the short-term solution, ArcleorMittal has developed a medium-term solution that will be available by 2017 and increase the lightweighting potential of the door while maintaining the same performance levels.

Both the short- and medium-term proposals will work on all types of cars; however, the company notes the requirements for doors vary, depending on the size of the car, which results in different weight reduction potential. On A-, B- and C-segment vehicles, a typical steel front door weights about 40 pounds. According to the ArcelorMittal global research and development team, in the small to mid-range cars “doors are heavy as they must include a loadpath to manage the forces generated in a frontal crash. In larger-segment vehicles, such as D-segment vehicles, this loadpath is incorporated into the body-in-white, making the door lighter.”

The company’s research also highlights steel as a cost-effective choice for automotive applications. The short- and medium-term solutions illustrate a cost savings of more than 30 percent. Both carbon fiber and aluminum are often proposed as alternatives to steel, but these materials cost more than advanced steels. According to ArcelorMittal, “for aluminum, the cost can be between three and six times more than steel, while carbon fiber is between 20 and 30 times more expensive.”

“Many key innovations in automotive steel products and solutions in the past 10 years have come from ArcelorMittal’s R&D teams. By applying the present solutions, a car door can be 30 percent less expensive than an aluminum door. Innovative steel solutions, like the ultra-lightweight car door solutions are further proof that steel is by far the most sustainable, the most versatile and the most affordable material to help carmakers produce lighter vehicles and achieve their weight-reduction targets on time,” said Greg Ludkovsky, vice president global R&D, in a press release. MM